Magnetic refrigeration technology at ambient temperature has been known for more than twenty years and the advantages it provides in terms of ecology and sustainable development are widely acknowledged. Its limits in terms of its useful calorific output and its efficiency are also well known. Consequently, all the research undertaken in this field tends to improve the performances of a magnetocaloric heat generator, by adjusting the various parameters, such as the magnetization power, the performances of the magnetocaloric materials, the heat exchange surface between the heat transfer fluid and the magnetocaloric materials, the performances of the heat exchangers, etc.
Relating to the magnetization power, it is important to integrate in a magnetocaloric heat generator a device that will allow to generate the most intense magnetic field possible. Indeed, the magnetocaloric effect of a magnetocaloric material is closely linked to the intensity of the magnetic field it is subjected to. Therefore, the stronger this magnetic field, the stronger the magnetocaloric effect of said magnetocaloric material, and, consequently, the higher the efficiency of the magnetocaloric heat generator.
Another aspect that can be improved in the magnetocaloric heat generators, and in particular in the generators wherein at least one component is rotating around a central axis, relates to the thermal bridges that appear between the various components and lead to a degradation of the temperature gradient between the hottest side, called hot generator side, and the its coldest side, called a cold generator side. As a result, the performance of a magnetocaloric heat generator, which is closely linked to this temperature gradient, is reduced.
Another point that can be improved relates to the optimization of the design, manufacture and assembly of such heat generator.
Furthermore, in addition to the need for an usable energy efficiency, a magnetocaloric heat generator must also have a reduced size or volume, allowing for example to integrate it in a household appliance, a vehicle, etc.
Such examples are in particular described in publications US 2010/0236258, FR 2 924 489, FR 2 937 182 and FR 2 904 098 of the same applicant, wherein the various components of the generators are stacked on a common shaft driven in rotation.